Field of the Invention
The present disclosure relates to a liquid crystal display. More specifically, the present disclosure relates to a liquid crystal display in which thin-film transistors in adjacent pixels share a contact hole thereby improving the aperture ratio.
Description of the Related Art
Liquid crystal displays refer to displays including a liquid crystal layer. Liquid crystal displays are driven by adjusting transmittance of light from a light source such as a backlight unit. Recently, the demand for liquid crystal display with a high resolution and a low power consumption is increasing.
A liquid crystal display is comprised of a plurality of pixels. In order to drive the plurality of pixels, the display includes a plurality of thin-film transistors. To improve the aperture ratio of liquid crystal displays, it is important to reduce the areas where thin-film transistors are formed, which do not transmit light. By improving the aperture ratio of liquid crystal displays, the brightness of liquid crystal displays can be increased to display brighter images. Additionally, liquid crystal displays can consume less power to achieve the brightness provided in existing displays.
In this regard, there have been numerous approaches to improve the aperture ratio of liquid crystal displays by reducing the regions where thin-film transistors are formed. For example, an approach has been proposed in which thin-film transistors in two pixels would share one gate line. In this approach, however, sharing agate line would require new designs for drivers of a liquid crystal display. Further, even the aperture ratio would not be improved substantially.
Also, reducing the regions where thin-film transistors are formed by reducing the size of a hole in a planarization film has been proposed to improve the aperture ratio. In this approach, however, the size of the hole in the planarization film cannot be reduced beyond a certain size due to thickness of the planarization film and the limitation of equipment such as an exposure device and an etch equipment.